Tratrix of said georg jseimann



G. HEIMANN, DECD.

. E. HECHT, ADMINISTRATRIX.

GRADED SERVICE ELECTROMECHANICAL TELEPHONE EXCHANGE SYSTEM.

' APPUCATION FILED nue za. 191.3. Pat t d j 1 1920 2 SHEETS-SHEET l- G. HEIMANN, DECD. E. HEC HT. ADMINISTRATRIX.

GRADED SE RVICE ELECTROMECHANICAL TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED Amza. 1913.

1 ,341,80 1 Patented June 1, 1920.

2 SHEETS-SHEET 2.

E s ,5! 1 a; 0| S1 g, E z l 661i; I "Q24 1 I g l T x I l k witnesses: Inventor:

W Georg Heimann. @f

UNITED STATES GEORG HEIMANN, OF CHARLOTTENBURG, BERLIN, GERMANY; ELSE HECH'I' ADMINIS- TRATRIX OF SAID GEOBG HEIMANN, DECEASED.

GRADED-SERVICE ELECTROMECHANICAL TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented June 1, 1920.

Application filed August 28. 1913. Serial No. 787,101.

To all whom it may concern Be it known that I, Gnouc HEIMANN, a subject of the German Emperor, residing at 35 Cauerstrasse. Charlottenburg, Berlin, Germany, have invented a Graded-Service Electromechanical Telephone Exchange System, of which the following is a true, clear, concise, and exact description.

My invention relates to automatic telephone systems and has to do more particu larly with systems of this kind in which some subscribers have greater privileges than others, the object of the invention being to provide devices by which the subscribers are compelled to pay more or less for a connection according to the scale of charges fixed by the telephone administration.

This object is attained by providing switch. controllers or impulse transmitters at the subscribers or sending stations which will enable the calling subscriber or the operator of a semiautomatic office to establish only such connections as the calling subscriber is entitled to. Further means are provided which will enable calling subscribe/rs to obtain privileged connections on paying an extra or special fee. 7

For convenience of description it will be assumed that in the telephone area indicated in Figure 7 there are five zones, a central zone A containing 6000 subscribers lines and four outlying zones B, C, D and E containing 1000 subscribers lines each. Switching apparatus would therefore have to be provided in the exchange (which may comprise one or more oflices) for the whole area I for 10000 lines.

It will further be assumed for example that graded telephone service is to be given to the subscribers of the telephone area in the sense that, according to the amount of their subscription, they will be allowed to make connections either only to the other subscribers in their own zone, or to subscribers own zone and in one or more other zones, or to subscribers in their own zone and in one or more other zones and in addition to a trunk exchange for inter-urban traffic. Any of these several connecting facilities could. be combined.

Before proceeding with the description of the manner in which a subscriber is restricted to his own district, the meaning of the symbols in Fig. 8 will be explained.

In. this figure the oblong figures A, B, C, D

and E represent central oflices in the similarly designated zone of Fig. 7. Another figure F, is shown which represents a trunk or long distance exchange. In the central ofiices A and B just sufficient switching apparatus is symbolically shown to enable calls to be followed through a few switch groups and to enable the devices that limit the subscriber to certain telephonic facilities to be clearly understood.

in the central ofiice B a single subscribers line is shownconnecting the subscriber S to the automatic switch system. A twoparty line is also shown connecting the two stations S and S to the office. The lines terminate at the oiiice in line switches a, b, which, on a subscriber e. g. S raising his receiver from the switchhook connects the line in a well known manner to a group selector. Instead of primary line switches a, I) only, secondary line switches may, of course, also be used. Only one group selector $9,. is shown.

The vertical line of the symbol tg, represents the shaft of a selector of the Automatic Electric Co. type and the short line projecting at a right angle fromthe vertical line represents the wipers of the selector. Adjacent to the vertical line are ten short thick lines in a vertical row and each of these thick lines represents a level of contacts. This description applies to all the other symbols of similar appearance in Fig. 8.

From each level of contacts of the first group selector $9, a number of trunks lead to a group of second selectors which establish the connections to a certain group of a thousand subscribers. As a 10000 system is being assumed, the ten levels of contacts of selector zip are connected to ten sets of trunks leading to ten different thousands.

It is assumed that the subscribers of the first six thousands are connected to oflice A, the subscribers of the seventh thousand to oilice B, of the eighth thousand to office C, of the ninth to oliice D and of the tenth thousand to office E. Hence, if a subscriber of the office B wishes to connect to a subscriber of the office A, he will have to lift the wipers of the first selector, that he is automatically connected. to by the line switch, to one of the six levels of contacts connected to the six sets of trunks leading to the oflice A. Only the first three of this six sets of trunks leading from the first group selector 09, are indicated in the figure by the lines 1, 2, 3. From the seventh contact level of the first group selectors 259 of which, of course, there are ten for every group of. hundred lines, although only one is indicated, a set of trunks? lead to the second group selectors b970, which extend the subscribers lines to the particular group of connectors fol, 702, etc., that makes the connections with the desired subscriber in the particular hundred group. f'cl, f01 are connectors which represent the group of connectors, that makes the connections with the first hundred of the thousand subscribers of the central otlice B. 7'02, 7 02, etc, are connectors, which represent the group of connectors for the second hundred subscribers of the central oflice B. There are, of course, in all, the ten groups of connectors in ofiice B for the ten hundred groups although only two such groups are indicated.

In the central oi'lice A two first selectors Z0 zg are symbolically shown. The substation lines 1 1 the first one of which is an individual line and the second a fourparty line, are connected, when a subscriber raises his receiver from the switchhook of his telephone, to a first selector tg or 6g, by a line switch 0 or (Z, or by a line finder, in a well known manner. From each of the contact levels of the first selectors, Z9 tg a set oi trunks leads to a group of second selectors that establishes the connections with. a particular group of a thousand subscribers. As in the otiice P, three sets of trunks 1, 2, 3 are indicated as connected to and extending from the contact levels of the first selectors 69 6g of otlice A. These three sets of trunks lead to second selectors ligl, 71.92, lay 3. 71 91 represents ten second selectors that extend talking connections to connectors 011, 021., 031 that establish the connections with the subscribers of the first thousand group 0-; the oifice A. 7Lg2 indicate a group 01' second selectors that extends connections to the subscribers of the second thousand, and 7 3 indicates the second group selectors tor the third thousand. 011, 021, 031 indicate three groups of connectors that make connections to the first, second and third hundred subscribers respectively of the first thousand subscribers. 012, 022, (-32 indicate the connectors of the first, second and third hundred groups of the second thousand and 013, 023, 038 represent connectors of the first, second and third luuulred grolu s of the third thousand. Only the few switches represented in Fig. 8 in oiiices A and B have been indicated as these are suificient for "following the routes ot a few calls through the switches of the automatic switching system and for showing how the connecting possibilities of the subscribers i'uay be limited to certain exchanges, zones, districts or facilities. The switches in the oilices C, D and E are arranged in an analogous manner to those in ofiice B. The number of switches and the grouping of some in the assumed 10000 system is practically as illustrated and explained in Az'ticcns lllrmuaZ of the Telephone pages 601, (302 and 603. The figure F in Fig. 7 represents a manual trunk or interurban oiiice. The subscribers can reach this inter urban ofiice through a set or sets 01' trunks 2' extending from the top ortenth contact levels of the second selectors 7tg3 that make the connections to the subscribers of the first thousand group in the office A. It is assumed that sets of trunks lead only from the first nine contact levels to nine sets of connectors in the third thousand group and that the tenth set of trunks, that would lead to the tenth group of connectors of the tenth group of one hundred subscribers lines is reserved for the connections that the subscribers desire to make through the inter urban office F.

It may be assumed for convenience that the circuits and mechanical construction of the switches are the same as shown in British Patent 30,458 of 1909 in which a so called three-wire system is disclosed, or as shown in the British Patent 1421 of 1910, which is a disclosure of the more modern two-wire system designed by the Automatic Electric Co. of Chicago.

From an inspection of Figs. '7 and 8 it will be apparent that the subscribers S, S S, have access to areas C and D through trunks S and 9. These subscribers may be prevented from obtaining connections with areas C and D by making their switch controllers incapable of sending the switching currents necessary for moving the brushes of the selectors to the contact rows representing the trunks 8 and 9. In a similar manier the subscribers of lines 1 and 1 may be barred from access to the areas or otlices C, D, E and F by arranging their switch controllers so that they are incapable of sending the current impulses required to move the contacts of the switches $9 739, on to the trunks leading to oiiices G, D and 1*) or to move. the selectors 72.0,, on to the trunks '4' leading to ofiice F.

The invention by which the subscribers switch controllers may be made incapable of sending the current impulses necessary for obtaining privileged connections or con nections with barred districts is exemplified in the drawings by a system in which the switch controllers at the sending stations are capable. of sending a maximum of ten impulses in a series. Devices are provided which prevent the switch controller from sending impulses whenever a subscriber or semi-automatic operator sets the controller to a position or positions that correspond to an unpermissible or privileged connection.

' Chicago.

connection first drops a coin into a chute or presses a recording button. The coin is however not cashed or the connection is not recorded until a special cashing or recording impulse flows in a well known manner from the exchange to the calling station at the moment the desired subscriber responds.

In the case of unsuccessful calls the cash ing or recording impulse does not flow, consequently when the calling subscriber replaces his receiver on the hookswitch the coin is refunded or the registering device is returned to its normal position without having recorded a connection.

The means by which cashing or recording impulses may be sent from the exchange and which coins are refunded or by which registrations of unsuccessful calls are prevented are well known and therefore form no part of this invention so that they need not be described herein.

The invention is illustrated in the accompanying drawings, Fig. 1 being a diagram of the connections of a contact device which prevents impulses being sent by the switch controller if this is set so as to correspond to a number representing a nonpermissible connection.

Fig. 2 is a front view of a switch controller such as provided at a subscribers station. In this figure some of the mechanical parts of the impulse preventing device are indicated.

Fig. 3 is a side View of Fig. 2 on an enlarged scale.

Fig. 4 is a top view of certain parts of Figs. 2 and 3 as seen by an observer standing behind Fig. 2.

Fig. 5 shows modifications of some of the parts shown in Fig. 3.

Fig. 6 shows how the general scheme indicated in Fig. 1 would be applied to devices constructed as shown in Fig. 3.

Fig. 7 represents a telephone area divided into one central. and outlying districts and Fig. 8 is a diagrammatic illustration of the switching apparatus employed in some of these districts.

The effect of the impulse preventing device can be explained by the aid of Fig. 1. In this figure, 6 represents the impulse sending contacts of a switch controller in a two wire system such as has been put into use in recent automatic telephone systems installed by the Automatic Electric Co. of V The impulses for controlling the switches at the central oflice are produced by openings of the contact 6. These open-- ings are caused in a well known manner by devices associated with a finger wheel 10, Fig. 2, these devices not being shown in the drawings. It is clear that the openings of the contact 6 can be rendered ineffective by short circuiting it and this is done by the impulse preventing device whenever the subscriber moves his finger wheel through an angle corresponding to a number that represents a non-permissible connection.

The impulse preventing device consists of an individual switch for each digit. Thus in a four digit automatic or semi-automatic system having numbers up to 9999 four individual switches 1, 2 and 4 are provided. In addition to the individual or digit switches the impulse preventing device consists of a digit selecting switch 5. The digit switches 1, 2, 3, 4 and the digit selecting switch 5 each have a movable contact that engages with a number of fixed contacts, the fixed contacts being represented in Fig. 1 by small circles.

The number of positions that may be assumed by the movable contacts of each digit switch is equal to the number of units contained in the particular digit of the calling numbers. Assuming that the decimal system of numbering is adopted the number of 0 positions to which the movable contact of each digit switch can be set is ten. The digit selecting switch 5 has as many fixed contacts as there are digits in the subscribers numbers. The digit switches are set by mechanism actuated in working the finger wheel of the switch controller. When the finger wheel is turned in order to select the thousands digit of the desired number, the movable contact of the first or thousands digits switch 1 is set to a position which corresponds to the number from which the finger wheel is turned.

If the subscriber turns the wheel from the fifth hole (see Fig. 2) to the stop 11, or in other words if the subscriber selects the fifth thousand, the thousands digit switch is moved to the fifth position and it then stays there until the subscriber replaces his receiver. WVhen the subscriber turns his finger wheel to select the hundreds digit of the desired number the hundreds digit switch 2 is set in a similar manner and this also applies to the tens and units digit switches 3 and 4:. Each time the finger wheel is moved forward the digits selecting switch 5 is shifted on one step, so that its movable contact engages with the first fixed contact after the thousands digit has been selected, with the second fixed contact after the hundreds digit is selected, and then in turn with the third and fourth fixed contacts on turning the finger wheel a third and fourth time to select the desired group of ten and to ultimately reach the desired line.

From the fixed contact of the digits selecting switch 5 electrical connections extend to various points or fixed contacts of the digit switches. The points to which these connections extend correspond to the number or numbers in the digits that it desired to make inaccessible to the subscriber.

Thus supposing that the subscriber is to be prevented from establishing connections with the subscribers located in the district that contains the subscribers having the numbers 6000 to 6999; the first fixed contact of the digit selecting switch 5 would be connected as shown in Fig. 1 to the sixth contact of the thousands digit switch 1. The subscriber or semi-automatic operator will then be unable to cause the selectors at the central oiiice to make connections with the sixth thousand, for when he moves his linger wheel through an angle that would ordinarily cause the number of impulses to be sent that would result in the selectors establishing connection with the sixth thousand, no impulses at all will be produced by the impulse contacts (3, because the contacts will be short-circuited (or rendered ineffective in any other suitable manner) by a by-path through the digit switch 1, which will be in position 6, and through the digit selecting switch 5, which will be in its position 1.

Fig. 1. illustrate. a case in which the sixth thousand is blocked, but in which cimnections with all the numbers in the sixth thousand excepting those oi? the third hundred can be obtained by opening the switcl 7, which would involve the payment of a special fee.

If, with the arrangement shown in Fig. 1, the dial is to be rotated to select the sixth thousand the subscriber would first push a button or drop a coin into a chute in order to open the contact 7. The contacting oi the movable contact 1 with its sixth contact will. have no eii'ect on the impulse contacts when the contact 7 open, for there will. then be no shunt through 1, T, 5 around the impulse contact 6 during the return movement of the dial 10 and the six breaks of (3 that take place during the return movement of the dial Will cause six impulses in the selector controlling circuit.

It the subscriber now turns his dial "from any hole 1, 2, 4, 5, 6, 7, 8, 9, 0 Fig. 2 to the stop 11 the movable contact of the hundreds digit switch 2, Fig. 1 will be set onto a corresponding lixed contact which is not connected in any way to the digit selecting switch and the breaks of the impulse contact 6 will be effective when the dial 10 is allowed to rotate back to its normal position. But it, when the dial 10 is turned the second time, it is rotated from the third hole 3., Fig. 2, to the stop 11, the movable contact 2 will be set onto its third fixed contact which is connected to the digit selecting switch 5. hen the dial is now allowed to return to its normal position the breaks of the impulse contact (3 will be rendered ineffective by a by-path through the digit switch 1, which is resting on its sixth contact, digit switch 2, which is resting on its third contact and through the digit selecting switch 5 which is resting on its second contact.

Just as it is possible to ordinarily block certain thousands or a certain thousand and to make all or certain of the hundreds of this thousand accessible by paying a special fee 2'. c. by operating a switch 7, it is also possible to ordinarily block all of the tens groups in a hundred or to make certain the tens groups accessible by paying a certain fee, a. 6., by 0 )ening the connection leading from the fixed contacts or contact of the hundreds digit switch 2. Thus in the example shown ii this connection were opened, all the tens groups in the 63rd hundred would be rendered accessible except the sixth and eighth tens group in this hundred, for if the dial 10, when it is operated a third time to select the desired" tens group, is turned from the sixth or eighth hole to the stop 11. the tens digit switch 3 would be set onto its sixth or eighth fixed contact and when the dial 10 is then allowed to rotate the breaks ot the impulse contact 6 will be rendered inetiective by a by-path leading through digit switch 1 which is in its sixth position, digit switch 2 which is on its third lixed contact, digit switch 3 which is on its sixth or eighth tixed contact, and through the digit selecting switch 5 which is on its third contact.

It will now be clear without further description, that, if desired, certain units of a tens group that is ordinarily blocked, could also be made accessible by opening the connection between the corresponding connection betv-ieen the particular fixed contact oi the tens digit switch and the digits selecting switch. Thus it is seen that any desired groups of lines of any size may be rendered ll1l'lU(fGS. l)l0 or they may be rendered. acce sible only on payment oi a special iee. it will be obvious that by having coin slots of diilerentsizes or by providing different push buttons cooperating with different contacts 7 controlling different groups ot lines (thousands, hundreds, ten or units) a complete graded service system with graded charges for connections to diii'erent telephone areas can be provided.

I will now describe a mechanical structure of the impulse preventing device indicated diagrammatically in Fig. 1. In Figs. 2 and 3 a. linger wheel 10 of the well known type used in conjunction with the Automatic Electric Cos system is shown. This linger wheel cooperates in the well known manner with impulse contacts 6 Fig. 1. In order to avoid unnecessary complication of the drawings only such parts as relate to the subject matter of this invention are shown.

In Figs. 2 and 3 each of the digit switches (Fig. 1) takes the form of a revoluble disk 13 fixed to a toothed retaining disk 15, Fig. 2. The revoluble disks are mounted on a hollow shaft 12, Fig. 3, through the center of which the finger wheel shaft extends. To each of the disks 13, is attached a spiral spring 14 which tends to turn the disk in a counter-clockwise direction. Each disk has a retaining pawl 16 which holds it in the position to which it is turned. The disks 13 are turned from their normal position in a clockwise direction by a propelling pin 18 and a propelling pawl 19. The propelling pin 18 is fixed to the finger wheel 10 and the pawl 19 is arranged to slide to and fro upon the pin 18. The pawl 19 has a roller 29 and a catch 21, Fig. 4, hinged or otherwise suitably fixed so as to assume the position illustrated. Each disk 13 has an opening 22,]

Fig. 2, and at the one side of the opening the disk is formed so as to serve as an inclined sliding surface for the roller 29, see Fig. 4.

The pawl 19 normally butts against the thick part 17 of the pin 18, being pulled into this position by a spring 20. When the pawl 19 is in this position its catch 21 and roller 29 are in front of the first disk 13, i. 6. between this first disk and the finger wheel 10.

When the subscriber, in calling a wanted number, gives the finger wheel the first turn the hinged catch 21 after moving a slight distance catches the right hand edge 22 of the opening in the first disk 13, Figs. 2 and 3, and turns the first disk in the direction contrary to the action of its spring 14. When the subscriber allows the finger wheel to execute its return movement the disk 13 is retained in its displaced position by its retaining pawl 16 and the roller 29 attached to the propelling pawl 19 now rides up on the inclined surface 30 (see Fig. 4) of the displaced disk 13 and enters into the space between the first and second disks 13, assuming the position shown in Fig. 3. Upon the second forward rotation of the finger wheel the second disk 13 is displaced by an angle corresponding to the number in the particular digit (hundreds digit in the present instance) and when the finger wheel returns to its normal position the propelling pawl rides up on the inclined surface 30 of the second disk and enters into the space between the second and third disks and so forth.

In a four digit system in which it is desired to make certain thousands, hundreds, tens and units inaccessible to the subscriber four disks 13 will have been displaced when the subscriber has sent in or endeavored to send in the four series of impulses representing the wanted number. The angle by which each of the disks will have been displaced will correspond to the number selected in the corresponding digit and according as this angle corresponds to an inaccessible number or not a pair of contacts 27, 28 will have been closed by the disk or not. The disks 13 are furnished with projections 26 which close or help to close the impulse preventing by-path through the pairs of springs 27, 28 a pair of springs being provided at each position that corresponds to an inaccessible number.

The springs 27 of all the pairs belonging to one disk 13 are interconnected and form the movable contact, the other springs 28 of the pairs are connected to the digit selecting switch as indicated in Fig. 1. At the end of the conversation, when the subscriber replaces his receiver, the switchhook lifts all the retaining pawls 16 out of the teeth of the disks 15 and the disks 13 are then rotated by their springs 14 back to their normal positions, in which all the openings 22 register with each other. and form a clear path for the passage of the propelling pawl 19 to its normal position to which it is pulled by the spring 20.

The digit selecting switch 5 takes the form of a number of sets of contact springs 24, 25, 31 Fig. 2, and of projections 23. Each disk 13 has a projection 23, which, as long as the disk is in its normal position, forces spring 24 against 31. As soon as disk 13 is moved out of its normal position, the projection 13 moves away from spring 24 and this spring then breaks its connection with 31 and makes connection with a spring 25. The spring 24 of the first disk is connected to the wire at the one side of the impulse contacts 6 like the movable contact of the switch 5, Fig. 1. The contact 25 of the first disk 13 is connected to the contact 24 of the second disk represented in Fig. 6 by the set of contacts II and the contact 25 of each other disk is connected to the con- .tact spring 24 of the succeeding disk as shown in Fig. 6. The contacts 31 of each disk are connected to the fixed contacts of the digit switches. 24, 25, 31 act exactly as the digit selecting switch 5, Fig. 1.

It is advisable to provide the switch con troller with a device that will prevent a subscriber from turning the finger wheel forward more than the required number of times, 6. four times in a four digit system. If such a device is not provided a subscriber who desires to connect to a particular thou sand for example, that is inaccessible in the ordinary way, could make a blind first turn of the finger wheel and could then give the finger wheel four turns and obtain the connection The second turn of the finger wheel would probably be effective and would cause the selectors to choose the desired thousand, because the digit selecting switch would be moved to its second position and the impulse preventing by-path through the thousands digit switch 1 and through the digit selecting switch 5 would not be closed.

But it a device is provided that prevents more than the required .number of turns of the linger wheel such abuses will be prevented, for the subscriber will then not be able to give the finger wheel more than three turns in addition to the blind turn and these three turns will not sullice to set up a connection to the switches at the central ollice.

This device may consist of the parts 10, 4L1, 42 indicated in Fig. 3. 40 is a projection fixed to the propelling pawl which, after the pawl has been slid forward a certain distance upon the square propelling pin, 2'. c. after the finger wheel has been turned certain number of times, will, when the finger Wheel turns back to its normal position, brush past a stop 11 which, by turning on its pivot 13, gives way to the projection 4L0, when this moves back c. in a counter-clock wise direction. But alter the proj ction 10 has receded behind the stop ll it will not be possible to turn the finger wheel forward again, because the projection 10 will then strike against the rear side of the stop 41 and this step will butt against a fixed pin 12, thus preventing the lifting of 41 by 40 and thereby preventing the projection 10 from brushing past the stop 11 in a clockwise direction.

To be able to use the linger wheel again, the subscriber is thus compelled to replace his receiver on the switchhook, so as to restore the propelling pawl 19 with the projection ll) to its normal position.

It is obvious that many other constructions may be devised to carry out the invention described herein without departing from its scope or spirit. F or example instead of making the digit switches 1, 2, 8, 4 electrically inter-dependent they may be made mechanically interdependent.

With mechanically interdependent digit switches tour disks similar to the disks 13 would be provided, but these disks instead of having contact controlling members 26 at the points corresponding to non-permissible connections, would have notches at their peripheries into which a spring member bearing upon their peripheries would enter, whenever the disks are turned through an angle correspoiuling to a non-permissible connection, and in so doing would close a short circuit about the impulse contacts 6. This is clearly shown in Fig. 5 in which 45 is a spring member pressing against the peripheries of the disks 46 416, 16 46 which represents the digit switches and are operated similarly as the disks Fig. 3, by

a pawl 21. The disks l6, 16 16 46 each have a notch ll in their normal positions into which enters the cross bar 18 of the spring member 415, so that in the normal po sition a short circuit is closed through 44;, -15 about the impulse contacts 6. Each disk -16 also has a notch or notches 19 4-9 19 49.

It will be assumed that the position of notch 19 is such that when the linger wheel is given its first turn from the third hole to the stop 11, Fig. 2, the notch 19 will register with the cross bar a8 allowing it to en ter the notch and to closs the contact 14:, 45.

This will prevent the subscriber from obtaining connections with the subscribers of the third thousand.

Connected to the short circuiting contact 1 1 is a digit selecting switch 5 similar to the switch 5 of Fig. 1. In the lead from the first contact of the digit selecting switch is indicated a contact similar to the contact 7, Fig. 1. By paying a special fee the sub scriber may gain access to the third thousand by opening the contact 7 If it is desired to debar the subscriber from connections to say the subscribers of the 86th hundred, a notch 49 would be provided in the hundreds disk 16 which would register with the crossbar 48 when the fingerwheel is turned for the hundreds digit from the sixth hole to the stop 11. This would result in the contact 14, 45 being again closed, and in the impulse springs 6 being short circuited thereby.

It will now be understood that by placing notches at the proper places on the pe ripheries ot the disks 4:6, 16, 16 16 any group of subscribers of any size may be made inaccessible' Instead of preventing the impulses by shunting the impulse contacts (3 by a by-path these impulse contacts can be made ineffective by opening a contact connected serially with the said impulse contacts.

I claim:

1. In a telephone exchange system with electro -mechanically controlled switches, talking stations, switch controlling circuits between the talking stations and the said switches, switch controllers at the said stations, circuit-ailectiug members in certain of the said controllers by which these controllers exercise a determined range of control over the said switches, and circuit-att'ecting members in other of the said controllers by which these other controllers exercise a range of control over the said switches, differing from that exercised by the said certain controllers.

2. In a system for connecting stations by electrically controlled devices, controllers each capable of being set to a number of corresponding positions, electrical circuit interrupters in said controllers, means for rendering inactive the said circuit interrupter-s when the controllers are set to a certain position.

In a system for connecting stations by electrically controlled devices, controllers each capable of being set to a number of po sitions, electri cal circuit interrupters in said controllers, means for placing an electrical shunt about the said interrupters when the controllers are set to a certain position.

4t. In a system for connecting stations by electrically controlled devices, controllers each capable of being set to a number of corresponding positions, electrical circuit interrupters in said controllers, means for rendering inactive the said circuit interrupters when the controllers are set to certain positions.

5. In a system for connecting stations by electrically controlled devices, controllers for controlling said devices, each controller being capable of being set to a position corresponding to a position on the other controllers, electrical circuit interrupters in said controllers, means for rendering inactive the said circuit interrupters when the controllers are set to a certain position.

6. In a system for connecting stations by electrically controlled devices, controllers for controlling said devices each controller being capable of being set to a position corresponding to a position on the other controllers, electrical circuit interrupters in said controllers, means for rendering inactive the said circuit interrupters when the controllers are set to a certain position, means for rendering inoperative the said means for rendering inactive the said circuit interrupters.

7. In a system for connecting stations by electrically controlled devices, controllers for controlling said devices each controller being capable of being set to a position corresponding to a position on the other controllers, means for rendering a controller inoperative when it is set to a certain corresponding position.

8. In a system for connecting stations by electrically controlled devices, controllers for controlling said devices each controller being capable of being set to a position corresponding to a position on the other controllers, means for rendering a controller inoperative when it is set to a certain corresponding station, means for rendering in effective the said. means for rendering a controller inoperative.

9. In a system for connecting stations by electrically controlled devices, controllers for controlling said devices each controller being capable of being set to a position corresponding to a position on the other controllers, electrical circuit interrupters in said controllers, means for placing a shunt about one said interrupter when a controller is set to a certain position, means for opening said shunt.

10. In a system for connecting stations by electrically controlled devices, a controller, an electrical interrupter, a device capable of being set in diflerent ways so as to produce different actions of the said interrupter, a means for rendering the said interrupter inactive when the said device is set a certain way.

11. In a system for connecting stations by electrically controlled devices, a controller with a plurality of possible adjustments each producing different connections through the said electrically controlled devices, means for rendering the controller ineffective on being adjusted so as to effect certain connections.

12. In a system for connecting stations by electrically controlled devices, an interrupter, a controller with a movable member for actuating the said interrupter and an adjustable member for rendering the said interrupter ineffective, said adjustable member being adjusted in accordance with the adjustment of the said movable member.

13. In a system for connecting stations by electrically controlled devices, a controller with an interrupter, a member for causing series of electrical circuit interruptions by said interrupter, an interrupter-affecting member corresponding to each of the said series of electrical circuit interruptions.

14. In a system for connecting stations by electrically controlled devices, a controller with an interrupter, a member for cansing series of electrical circuit interruptions by said interrupter, an interruptenafi'ecting member corresponding to each of the said series of electrical circuit interruptions and a switch that connects progressively to the said interrupter-affecting members.

15. In a telephone exchange system with electromechanically controlled switches), talking stations, switch controlling circuits between the talking stations ,and the said switches, switch controllers at the said stations, circuit affecting members in certain of the said controllers by which these controllers exercise a determined range of control over the said switches, circuit-affecting members in other of the said controllers by which these other controllers exercise a range of control over the said switches differing from that exercised by the said certain controllers, and means in certain or all of the said controllers for altering the range of control of the circuit-affecting members.

In witness whereof I hereunto subscribe my name this 19th day of August A. D.

GEORG HEIMANN. Witnesses:

OSCAR DEPNER, LonIs VANDORN. 

